Thermal timer for toasters



AP 1,`1941- J. R. GoMEnsALL.

THERMAL TIMER FOR TOSTERS FledMarCh 29, 1940 `3 Sheets-Shee-t 1 Olne.

April l, 1941- J. RGOMERSALL. 2,237,100

THERMAL TIMER FOR TOASTBRS Filed Maron 29, 1940 s sums-sheet 2 asf* 5s -ss H 21 l 9 l |27 i 9| se .sa

, mns m l Ffa-6. |21 92 |23 4" |31 l. v |43 99 3 l's l |z| g I 23 i o lo Inventor-.- v |47/ 145:07 |09 J'ohnRGomersaLl y I 9|*- v o 'zT- G 3 .J4/Mgg@ Patented pr. 1, 194i 2,237,100 THERMAL TIMER FOR. TOASTERS John R. Gomersall, Elgin, Ill., assigner to McGraw Electric Company, Elgin, lll., a corporation of Delaware Application March 29, 1940, Serial No. 326,576

8 Claims.

My invention relates to automatic electric toasters and more particularly to thermal timing means to determine the duration of `a toasting operation.

An object of my invention is to provide a relatively simple thermal timer structure which may be associated with an automatic electric toaster and control the duration of successive toasting operations thereof.

Other objects of my invention will either be apparent from the description of a form of device embodying my invention now preferred by me or will be specifically pointed out therein and set forth in the appended claims.

In the drawings, l

Figure 1 is a central vertical sectional lview on the line l-I of Fig. 2, the parts being shown in non-toasting position,

Fig. 2 is a front elevational and sectional view on the line 2-2 of Fig. 1, the parts being shown in non-toasting position,

Fig. 3 is an enlarged fragmentary front sectional view taken on the line 3--3 of Fig. 6, showing the parts in toasting positions,

Fig. 4 is a fragmentary sectional plan view on the line 4-4 of Fig. 3 showing the parts in toasting position, Y

Fig. 5 is a fragmentary detail sectional view on the line 5-5 of Fig. 4 showing the parts in normal or non-operating position,

Fig. 6 is a fragmentary View showing the front end of the toaster as seen when looking at the bottom of the front end portion of the toaster with the cover member removed.

Fig. 7 is a perspective View showing some of the parts as seen in Fig. 6, in non-operating position and on a slightly enlarged scale,

Fig. 8 is a fragmentary detailed sectional view y on the line 8-8 of Fig. 9 showing part of the means for varying the operating time of the toaster,

Figs. 9, 10, 11 and 12 are fragmentary detail sectional views on the line 9-9 of Fig. 3 showing the parts in the positions occupied by them during the heat-up cool-off operation of the bimetal bar,

Fig. 13 is a fragmentary detail sectional view taken on the line 13-13 of Fig. 12, and,

Fig. 14 is a wiring diagram showing the switches in initial or neutral positions.

I have elected to show my novel form of thermal timer and detent release structure as associated with a two-slice oven type automatic toaster in which the toast-heating elements are energized only during the successive toasting operations.

A toaster, designated generally by the numeral 2|, comprises a skeleton base frame 23 which may be made of a suitable moulded composition material and which has mounted thereon against its upper face a bottom plate 25 and which also has mounted adjacent its bottom edge a crumb tray 21, all in a manner well known inthe art.

The toaster includes further a plurality, of planar vertically extending heating elements 29 each of these heating elements including one or more plates 3l of thin electric insulating material, such as mica, having wound thereon resistor strip or wire 33. While I have not illustrated the individual heating elements 29, they are already old and well known in the art and their location and arrangement in a toaster structure of this kind is clearly shown in Ireland Patent No. 2,001,362 assigned to the same assignee as is the present application.

The toaster structure includes further a rear intermediate plate 35 and a front intermediate plate or wall 31 cooperating with the outermost heating elements 29 to provide toasting chambers in the toaster structure, the number of such toasting chambers constituted by spaced pairs of vertically extending toast-heating elements and portions of the front and of the rear intermediate walls equaling the number of slices of bread which can be toasted simultaneously.

The toaster structure includes further a casing 39 comprising a front and a rear Wall and two side wallsA cooperating with a cover 4I to substantially completely enclose the toasting chambers as well as a mechanism chamber 43 located in front of the front intermediate Wall 31.

I may provide a vertical standard 45; in the mechanism chamber 43, the lower end of this standard being supported as by the top p'art of la thermal timer casi-ng 41 while the upper end thereof may be supported in proper operative position by a bracket 49 secured to the front intermediate wall 31.

One or more bread carriers 5|, equal in number to the number of slices of bread which can be toasted simultaneously and for which the toaster structure is designed and constructed, are arranged to have reciprocal vertical movement in the individual toasting chambers. The bread carriers have rear end portions extending through slots 53 in the rear intermediate wall and front end portions extending through slots 55 in the front' intermediate wall 31 so that the bread carriers may be guided in their respective vertical movements into upper or non-toastingpositions and into lower or toasting positions relatively to the toast-heating elements hereinbefore described. Means for biasing the carriers into their upper non-toasting positions may include a coil spring 51 having its lower end secured to the bread carriers in a manner to be hereinafter described while its upper end is secured to bracket 49.

Means for causing downward movement of the carriers may include acarriage plate 59 verti-- cally slidable upon the standard 45 and having rearwardly extending lateral portions 9| mechanically connected to the front end portions of the bread carriers, all in a manner well known in the art. An auxiliary carriage member 99 may be loosely mounted on carriage plate 59 and have a forwardly extending bar portion 95 on which is mounted an actuating knob 61 upon which pressure may be applied by an operator to cause downward movement of the carriage plate and of the carriers against the bias of coil spring 51.

A twin conductor cord 99 is provided and extends into the toaster structure through a bushing 1| of electric insulating material, the conductors being connected to a plurality of terminal members 19, all in a manner well known in the art. All of the details hereinbefore described are already old and well known in the art and have been described only in order to more clearly set forth the operation of the thermal timer positioned within the auxiliary casing 41.

'Ihe carriage plate 59 has mounted thereon a roller'15 on a stub shaft or pin 11, secured to a bracket 19, this roller and pin moving downwardly with the bread carriers, the roller being adapted to engage a catch member 19, shown more particularly in Fig. 5 of the drawings. The catch member 19 is provided with an upper hooked portion 9| and is pivotally mounted on a pin 83 which pin may be supported by a slotted guide member 95 also shown in Fig. 5 of the drawings. The downwardly moving roller 15 will engage an inclined surface of the central portion of member 19 causing turning movement thereof in a clockwise direction against albiasing spring 91 until an extension 99 thereof engages a pivotally mounted detent 9|. The upper end of detent arm 9| is provided with a hooked portion shown, for instance, in Figs. 9 to 12 inclusive so that it may engage end portion 99 of the catch 19 and hold it in locking or holding position with regard to the roller 15 to thereby cause the bread carriers to remain in their lowered position until released therefrom by the thermal timer hereinafter to be described. 'I'he detent arm 9| is pivotally supported on a bracket plate 92 secured against the bottom surface of the top part of casing` 41.

'I'he carriage plate 59 is provided with a lateral projection 99 which bracket portion is adapted to engage an actuating rod 95 of a control switch for the toast-heating elements. this switch comprising a substantially fixed contact 91 mounted on a plate 99 of electric insulating material within the housing 41 and including also a spring contact arm |9| adapted to be pressed downwardly by' actuating rod 95 through a compression spring |93 both of which are positioned in a tubular guide |95 secured to the top wall of casing 41. All of the details hereinbefore described are old and well known in the art and constitute nov part of my present invention.

'I'he timer includes a bimetal bar 91 having one end iixedly supported on a bracket |99 which bracket may be mounted on electric-insulating plate 99 or in any other suitable manner. An auxiliary heater is insulatedly mounted on bimetal bar |91 and, as shown in Fig. 14 of the diagram of connections, this auxiliary heater,

ward the left as is shown more particularly in Fig. 10 of the drawins.

I provide a detent-actuating bar ||9 which has one end thereof pivotally connected to an arm ||4 pivotally supported on the same pin as is detent 9|. The other end of actuating bar ||9 is provided with a shouldered end portion ||5 of part of its width while the other part thereof has an angularly extending cam surface ||1. Arm 9| is supported on the same pivot pin as is arm |I4, but is movable relatively thereto to permit independent movement of arm 9| in a clockwise direction as seen in Figs. 9 to 12 when the extension 99 of member 19 is locked in position by member 9| when the bread carrier is held in toasting position. Arm 9| has a lateral projection ||9 thereon adapted to be engaged by arm |4 when the latter is moved in a clockwise direction by bar ||9 because of the latter being moved toward the right (as seen in Fig. 1l) by the cooling bimetal bar |91 as will be described later.

Bar ||9 is provided with an extended slot ||9 therein, a reduced portion of a pivotaily mounted lever arm |2| iitting into this extended slot. The other end of lever arm |2| engages a resilient contact arm |29 of an auxiliary heater control switch, the other part of this switch including a substantially ilxed contact arm |25. Contact arm |29 is so constructed that it tends to engage the iixed contact |25. Lever arm |2| is provided with an upwardly extending portion |21 having a hooked end and extending through the upper wall of auxiliary casing 41 as will be seen for instance in Figs. 1 and 2 of the drawings. A spring bar |29 engages the upper hooked end of projection |21 to cause extension |21 to be biased upwardly whereby that end of lever arm |2| engaging spring contact arm |23 is moved downwardly to thereby hold the auxiliary switch comprising members |29 and |25 in open or auxiliary heater energizing position. It'may be here pointed out that the lower end of carriage plate 59 is adapted to engage the outer movable end of spring arm |29 when the carriage plate has been moved into its lowermost position to remove the bias of extension 21 and of lever arm |2| hereinbefore described. The bias of lever arm |2| provided normally by spring bar |29 has the result that actuating bar ||9 is normally and initially held out of the path of movement of the bimetal bar |91 during the heat-up period thereof when, as hereinbefore stated, it will move -toward the-left as seen in Figs. 9 and 10 of the drawings.

A memberfor holding the actuating bar ||3 in its normally biased position includes an arm |3| 4pivotally mounted at its lower end on plate 92. 'I'he movable end of arm |9| is provided with a projection |93 adapted to engage against one edge of the shouldered part ||5 of detentactuating bar H9. 'I'he movable end of arm |9| is provided with a tubular portion |35. A rod |91 having a cam-shaped projection |99 (see Fig. 6) is adjustably movable within the tubular member |95 as by a link |4| connected to a crank arm or plate A|43 which is mounted on and adapted to be turned by a knob |44 mounted on a short Ashaft |45 (see Figs. 2 and 6). Since one end of the bimetal bar |91 is held in xed position, the main portion thereof will flex into arcuateshape so that substantially only the end portion of the bimetal bar will engage cam surface |39 and it is obvious that if this cam surface is in the position shown in Fig. 6 of the drawings, su'ch engagement will occur sooner than would be the case if the shaft |45 had been turned by its knob to cause movement of cam surface |39 toward `the right, as seen in Fig. 6. It is obvious that the time required to heat bimetal bar |01 to the temperature necessary to cause it to engage the right-hand end of cam surface |39, (when the latter is in the position shown in Fig. 6) will be less than the time required to cause heating of the bimetal bar and engagement thereof with the left-,hand'end portion of cam surface |38 thereby providing means for varying the duration of a toasting operation.

It has already been hereinbefore stated that spring arm |29 is moved downwardly out of engagement with the projection |21 when the bread carriers are in their lowermost or toasting positions, the positions of parts of the timer and of the carriers then being that shown in Fig. 3 of the drawings so that the tendency of spring contact arm |23 is to press the right-hand end of lever arm |2| upwardly thereby holding the outer end of actuating bar ||3 downwardly against projection |33 during the heating-up period of the bimetal bar.

Fig. of the drawings shows the next step in the operation of the blmetal bar when it has engaged cam surface |39 and caused turning movement of arm |3| in a counter-clockwise direction, as seen in Figs. 9 to 12 inclusive, whereby projection |33, which has been acting as a stop member relatively to actuating bar H3, is moved out of engagement with actuating bar ||3 and resultant closing movement of spring contact arm |23 with its cooperating contact |25 whereby auxiliary heater is short-circuited or de.- energized.

It will be noted by reference to Fig. 10 oi the drawings, that the shouldered end of bar ||3 has been moved into a position where it is in the path of return movement of the now cooling bimetal bar and Fig. 11 of the drawings illustrates the next step during the cooling of the bimetal bar when it has engaged shouldered end ||5 of the actuating bar H3, caused longitudinal movement thereof with resultant turning movement, in a clockwise direction, of the detent arm 9| because A of the engagement of arm ||4 with projection H6, whereby release thereof from catch portion 89 is eiected with resultant turning movement of the catch 19 in a counter-clockwise direction and resultant upward movement of the bread carriers into their upper or non-toasting positions and simultaneous opening of the main switch controlling the toast-heating elements. A

shock absorber structure |48 comprising an airv cylinder and a piston and piston rod may be connected to the bracket 49 and to the carriage 59 in a manner well known in the art.

Since spring arm |29 was held in its downwardly position, as shown in Fig. 3 of the drawings, during a toasting operation, and since it will be disengaged from carriage plate 59 when the latter moves upwardly, its biasing effect on projection |21 will now again be operative and cause upward movement of actuating bar ||3, or, as may be stated in other words, will cause a turning movement of bar |2| on its pivot with resultant turning movement of bar ||3 in a clockwise direction so that the angular surface ||1 willv move past the stop member |33 to permit of arm |3| being turned in a clockwise direction-under the influence of a small spring |41 provided for that purpose. It may be here pointed out that spring |41 has one end thereof connected to arm 13| and its other end connected to detent arm 9| 75 thereby biasing both members in the desired normal or initial positions. A stop pin |69 fixed in bracket plate 92 limits the turning movement of arms Si and i3 in one direction. Y

It will be evident from the above description that I provide a relatively simple mechanical structure actuable in sequence in certain predetermined steps by a bimetal bar having a exing end portion adapted to engage an adjustable pivotally .supported member which, when moved byl the heated binetal bar, will cause movement of a detent-actuating bar into the path of return movement of lthe bimetalV member during the cooling thereof. The bimetal bar is effective, as has hgreinbefore been described, to cause deenergization of a small auxiliary heatingelement thermally associated therewith when the bimetal bar has been heated .to an adjustable predetermined temperature to thereafter cause cooling of the bimetal bar under a draft of air owing through the auxiliary casing 41 as by louvers |5| shown in Figs. 2 and 3 of the drawings.

It will be further evident from the hereinbefore described operation of the device that a spring bar is made effective upon upward movement of the bread carriers to cause return to their initial positions of certain parts of the timer so that it is only necessary to -again move the bread carriers-and slices of bread placed thereon downwardly by pressure on the knob 61 to initiate another toasting operation.

Various modifications may be made in the structure herein described and shown in the drawings without departing from the spirit and scope of my invention and all such modifications are to be considered as being covered by the appended claims.

I claim as my invention: f

l. A thermal timer for an automatic electric toaster comprising a toast-heating element, a control switch therefor normally yielding biased to,

ally connected to the detent arm, a member spring biased to normally hold the other end of the detent-actuating bar out of the path of movement of the bimetal bar when the same is being heated and engageable by said bimetal bar when the same has been heated to a given temperature to be moved out of holding engagement with the detent-actuating bar to cause the latter to move into the path of movement of the bimetal bar, the cooling bimetal bar engaging and moving said detent-actuating bar to cause releasing movement of the detent arm with resulting opening of the control switch.

2. A thermal timer for an automatic electric toaster comprising 'a toast-heating element, a bread carrier movable into toasting and nontoasting positions relatively to the toast-heating element, means to normally yieldingly bias the carrier into non-toasting position, means to move said carrier into toasting position and a pivotally mounted detent arm effective to hold the bread carrier in toasting'position, said thermal timer including a bimetal bar having a portion free tomove in response to temperature changes, means to cause heating and then cooling thereof, a detent-actuating member having one end operatively engaging said detent arm, means fornormally holding the other end of the detent-actuating member out of the path of movement of the bimetal bar when the same is heated and engageable by the bimetal bar when it has been heated to a predetermined temperature to be moved thereby out of holding engagement with the detent-actuating arm to cause Ithe latter lto move into the path of movement of the bimetal bar, the cooling bimetal bar engaging and moving said detent-actuating arm to cause releasing movement of the detent arm and resultant movement of the bread carrier into nontoasting position. l

3. A thermal timer for an automatic electric toaster comprising a toast-heating element.. a bread carrier movable into toasting and nontoasting positions relatively to the toast-heating element, means to normally yieldingly bias the carrier into non-toasting position, means to move said carrier into toasting position and a pivotally mounted detent arm effective to hold the breadcarrier in toasting; position, said thermal timer including a bimetal bar having a portion free to move' in response to temperature changes, an electric heater in heat-transmitting relation to the bimetal bar, a switch for shortcircuiting said electric heater normally biased to closed position, a detent-arm-actuating bar having one end connected to the detent arm, a pivotally mounted member spring biased tonormally hold the other end of the detent-arm-actuating bar out of the path of movement of the bimetal bar, a lever arm `pivotally mounted intermediate its ends having: one end operatively engaging said electric heater switch and having its other end interiltting and moving with said actuating bar, spring means engaging said lever arm to normally cause it to hold the shortcircuiting switch in open position, meansconnected with the bread carrier to counteract said spring means when the carrier has been moved into toasting position, the heated bimetal bar engaging said pivotallymounted member at a predetermined temperature thereof, to move it out of holding engagement with said actuating bar, cause the short-circuiting switch to move to closed position to deenergize said electric heater and cause the'actuatlng bar to move into the path of movement of the cooling bimetal bar, said cooling bimetal bar engaging Seid actuating bar to cause detent arm releasing movement, return of the bread carrier to non-toasting position, termination of the counteracting eiect on the spring means, movement of the short-circuiting switch to open position and `re l turn of the pivotally mounted member to its holding position.

4. A device as set forth in claim 2 in which the means engageable by the bimetal bar is provided with a cam surface contacted by the heated bimetal bar and manual means for moving the ased to open position, means for closing said switch to initiate a toasting operation .and a detent means for holding saidswitch in closed position, said thermal timer comprising a bimetal bar having a portion thereoffree to move under temperature changes, means to cause heating and then cooling thereof, a detent-actuating bar, a member for normally holding the detenta-actuating bar out of the path of movement of the moving portion of the heating bimetal bar and engageable by said bimetal bar when it has been heated to a predetermined temperature to be moved out of its holding engagement with said datent-actuating bar to cause the latter to move into the path of movement of the bimetal bar and simultaneously to cause cooling of the bimetal bar, said bimetal bar engaging said detentactuating bar at a predetermined lower' temperature to cause detent-releasing movement thereof and opening of the switch.

7. A device as set forth in claim 6 in which the member engageable by the heating bimetal bar includes means actuable at the will of an operator to vary said predetermined temperature at which engagement occurs, the lower predetermined temperature at which the cooling bimetal bar engages said detent-actuating ybar remaining constant.

8. A thermal timer for an automatic electric.

toaster comprising a toast-heating element, a control switch therefor yieldlngly biased to open position, means for closing said switch to initiate a toasting operation and a detent arm for holding said switch closed, said thermal timer including a bimetal bar having a portion free to move under temperature changes, an auxiliary electric heater in heat-transmitting relation to the bimetal bar, a switch for controlling the auxiliary heater and inherently biased to heaterdeenergialng closed position, a lever arm engaging said auxiliary heater switch, a spring engaging said lever arm and normally eiIective to engage and cause the lever arm to hold the auxiliary heater switch in heater-energizing open position and moved out of engagement with the lever arm by said switch-closing meanswhen closing said switch, a detent-actuating bar pivotally connected .at one end to said detent arm and having a shouldered and angularly-extending other end pivotally connected with said lever arm, a pivotally-mountedi member normally biased into engagement with said other end of said detent-actuating bar to hold the latter out `of the path of movement of the heated bimetal bar, said bimetal bar engaging said pivotallymounted member at an adjustable predeterfmined temperature to move said member and cause movement of the lever arm and closing-of -the auxiliary heater switch and cause said deytent-actuating bar to move its shoulder into the path of'movement of the cooling bimetal bar simultaneously, said bimetal bar engaging the shouldered end portion of the detenta-actuating -bar at a predetermined lower temperature to 'cause release movement of the detent, opening of the control switch for the toast-heating element, reengagement of the lever arm by said spring with resultant opening ofthe auxiliary heater switch and movem'ent of the detent-actuating bar out of the path of movement of the bimetal bar,

JOHN R. cioiluazasllm. 

